1. Put the gelatine leaves into a bowl of cold water to soak for 10 minutes.
2. Grease 6 small pudding moulds or ramekin dishes.
2. Put the cream and milk into a heavy bottomed saucepan and bring to the boil.
3. Reduce the heat, add the sugar and vanilla extract, and stir until the sugar is dissolved.
4. When the gelatine has finished soaking, remove it from the water with clean fingers and add to the cream mixture.
5. Stir until dissolved.
6. Pour the mixture into the greased moulds/ramekins and allow to cool, then refrigerate overnight.
7. To serve, carefully dip the bowl into hot water for 1 second, then turn out on to a damp plate. Position the panna cotta, then garnish with a sprig of mint.